Drilling apparatus



w. w. PAGET DRILLING APPARATUS Jan. 25, 1944.

Filed Jan. 8, 1941 s Sheets-Sheet 1 g Q Q 5 W. W. PAG ET DRILLINGAPPARATUS Jan. 25, 1944.

3 Sheets-Sheet 2 Filed Jan. 8, 1941 Patented Jan. 1944 DRILLINGAPPARATUS Win W. Paget, Michigan City, lull, assignor to SullivanMachinery Company, a corporation of Massachusetts Application January 8,1941, Serial No. 373,586

24 Claims.

This invention relates to drilling apparatus, and more particularly toimprovements in rotary drilling apparatus of the high speed typeespecially designed for use in boring holes in relatively hard materialssuch as hard rock or the like.

An object of this invention is to provide an improved drillingapparatus. Another object is to provide an improved drilling apparatushaving improved feeding means and improved means for controlling thefeeding means. A further object is to provide a fluid actuated feedingmeans for a rotary drilling apparatus having improved means responsiveto the resistance to rotation for automatically controlling the feedingpressure.

Still another object is to provide improved means for controlling theflow of motive fluid to the.

feeding means and the venting of fluid from the feeding means. A furtherobject is to provide an improved rotary drilling apparatus of the highspeed type having improved means for automatically controlling thefeeding pressure on the drill bit so as to maintain an automaticallycontrolled and regulated feeding pressure during the drilling operation.A still further object is to provide an improved feed controlling meanshaving difierent degrees of responsiveness to different degrees ofresistance to drill bit rotation whereby difierent feed controllingfunctions may be effected. Still another object is to provide animproved feed .controlling means operatively connected in the drivebetween'the bit rotating motor and the drill rod whereby relativecontrolling movement between the parts may occur when certain drillingconditions are encountered so that the drilling pressure may beautomatically regulated in an improved manner. A further object is toprovide an improved feed controlling means embodying relatively movablecontrolling connections between a motor driven element and a cooperatingelement driven thereby, the latter element being operatively connectedto the drill bit, whereby variations in the resistance to drill bitrotation automatically efiect relative motion between the saidelements,- and the said controlling connections embodying means fortransmitting such relative motion to a feed controlling element. A stillfurther object is to provide an improved feed controlling meansautomatically responsive to resistance to drill bit rotation forregulating the flow of motive fluid to the feeding means within certaindegrees of resistance to drill bit rotation, and for automaticallyinterrupting suchflow when the resistance to drill bit rotation reachesa predetermined point, and embodying means for automatically venting thefeeding pressure when such point is, for any reason, exceeded. A stillfurther object 'is to'provide an improved torque-controlled valve meanshaving improved control means responsive to torque variations resultingfrom changes in load on the drill bit rotating means, forautomaticallycontrolling the feedings means. A still further object isto provide an improved torque-controlled valve means having improvedoperating means whereby 'the valve position may 'be automaticallychanged in accordance with torque changes on the drill rotating means,in an improved manner. These and other objects and advantages of theinvention will,- however, hereinafter more 'fully appear.

In the accompanying drawings there is shown for purposes of illustrationone form which the invention may assume in practice.

In these drawings:

Figs. 1 and 2, when taken together, constitute a view in longitudinalvertical section through an illustrative embodiment of the improveddrilling apparatus, parts being shown in elevation to facilitateillustration.

Fig. 3 is an enlarged fragmentary sectional view taken on the plane ofFig. 1, illustrating the improved feed controlling means.

Fig. 4 is a detail vertical sectional view taken substantially on line4-4 of Fig. 3.

Fig. 5 is a .detail sectional view taken on line 55 of Fig. 4.

Fig. 6 is a detail sectional view illustrating one of the fluidconducting passages of the feeding means.

Fig. 7 is an enlarged horizontal sectional view taken substantially online 1-1 of Fig. 1, illustrating the manual control valve. 4

Fig. 8 is a detail sectional view, taken substan tially on line 8-8 ofFig. 7, showing and below the plane of Fig. 7.

Fig. 9 is a detail vertical sectional view taken on line 9-9 of Fig. 4.

Fig. 10 is a vertical sectional view taken on line Ill-10 of Fig. 3,illustrating the torque-conparts above sectional view ftakensubstantially on the plane including line l3.l3 clv Fig. 12.

Fig. 14 is a atic view illustrating the fluid system and the associatedcontrol means.

In this illustrative embodiment of the inventionthere is shown a. rotarydrilling apparatus of the high speed type especially designed for use inboring holes in relatively hard rock or the like and adapted to use withabrasive type bits, commonly known as diamond bits. The drillingappaartus may be of the same general type as that disclosed in mycopending application Serial No. 322,267, filed Mar. 5, 1940, sincematured into Patent No. 2,288,543 dated June 30, 1942, and as a wholecomprises bit rotating means, generally designated I, fluid actuatedfeeding means, generally designated 2, manual feeding means, generallydesignated 3, and supporting and guidin means, generally designated 4.

The supporting and guiding means 4, which is similar to that shown inthe copending application above referred to, comprises a trunnionsupport 5 having a swivel plate 6 adapted to be secured in the saddlemounting of a conventiona1 rock drill support.

The fluid actuated feeding means 2 likewise is similar to that shown inthe'aforesaid copending application and comprises a reciprocable feed,cylinder I slidably guided in a bore 8 in the trunnion support andcontaining a reciprocable feed piston 9 having a tubular piston rod lextending forwardly through paekines ll carried by the front head l2 ofthe feed cylinder. The cylinder head I2 is suitably secured to the feed0371- inder and closes. the front end of the cylinder bore, while therear end of the cylinder bore is closed by a rear cylinder head l3likewise suitably secured to the cylinder. The'front and rear cylinderheads are engageable with the end surfaces of the trlmnion support 4 tolimit reciprocable movement of the feed cylinder in the trunnion supportbore. Secured to the front end of the feed piston rod I0 is a headmember H which closes the front end of the piston rod bore, and the rearend of the piston rod bore is closed by a head element l5 whichconstitutes an element of the feed piston 3. The feed piston is doubleacting and has packings l3 sealingly engaging the walls of the cylinderbore and secured in position by the members I! and [8, in turn held inposition on the head element l5 of the piston rod between a shoulder l9and an end lalsate 20 detachably secured to the head element Nowreferring to the manual feeding means 3, it will be noted that securedwithin the trunnion support 5 is a tube 2| having its axis arranged inparallelism with the feed cylinder axis, and extending longitudinallythrough this tube and rotatably mounted in depending bosses integralwith the front and rear cylinder heads l2 and I3 is a tubular feed.screw 22 coacting with a non-rotatable feed nut 23 secured within thetrunnion support. The forward end of the rotatable feed screw is fixedagainst axial displacement with respect to the feed cylinder and'extendsrearwardly through the rear head l3 and has secured thereto, at its rearend, a hand crank 24 having a grasping portion 25. Carried by the handcrank is a suitable plunger lock 26 engageable within a locking recess21 in the rear cylinder head for locking the feed screw against rotationduring automatic feeding of the drill.

'Ihreadedly secured at 3| within this control head is a member 3| havinga sleeve portion fittin within the bore of the feed screw at the forwardend of the latter, and secured, as by welding at 32, to this sleeveportion is a tube 33 extending centrally within and in telescopicrelation with the feed screw, in the manner shown in Figs. 1 and 2. Thetube 33 has a sliding fit with the walls of the bore of the feed screwand serves to maintain the feed cylinder against rotation within itsbore on the trunnion support and in efiect acts as a lateral slidingguide for the drill. The manual feeding means and the sliding guidestructure are likewise clearly described in the application mentionedabove.

The drill bit rotating means I comprises a rotary motor 35, herein ahigh speed electric motorof the totally enclosed type, comprising astator casing 36 provided with front and rear heads 31 and 38, thelatterbeing formed preferably integral with the control head 29, asshown in Fig. 1. The motor parts are held in assembled relation by tiebolts 39. Clamped in position within the motor casing by the front motorhead is an inner head member 40, while clamped within a bore 4| inthecontrol head by the screws 28 are butting head elements 42 and 43. Themotor has a usual field 44 and an armature rotor 45, the latter beingsecured to an armature shaft 46. The forward endof this armature shaftis joumaled, in a manner to be later explained, within bearings 41supported within the front head members 31 and 40 and at its rear endwithin a bearing 48 supported within the head element 42. It isaccordingly evident that the motor casing is rigidly secured to thecontrol head, and electrical energy may be conducted to the windings ofthe motor from any convenient source through a conventional connectorplug 49 mounted on the control head and connected through wiring 50 toan automatic switch 5! which is arranged in a chamber 52 in the controlhead for efiecting stopping and starting of the motor in the mannerclearly described in the copending application above referred to. Theforward end of the armature shaft is supported within a shaft 53 andthrough this shaft is journaled within the bearings 41, and the shaft 53As above mentioned, the forward end of the feed piston rod l0 supports ahead member l4 (-Fig's. 1 and 6), and rigidly secured, as by screws 28,to this head member is a control head 28.

carries a chuck 54 which receives the supporting means for the drill rodwhich carries the drill bit.

The means for supplying fluid, preferably liquid under pressure, to thefluid actuated feeding means 2 comprises a liquid supply chamber 55formed in the control head 29, and liquid under pressure may beconducted to this chamber through a strainer 56 from a supply passage 51formed in a head member 58 secured to the control head. Also formed inthe control head 29 is a longitudinal bore 59 having arranged therein aported valve bushing 60 in which a control valve 6| is reciprocablymounted. This valve is of the sliding spool type and is operated by avalve adlusting screw 62 engaging a non-rotatable nut 63 formed withinthe sleeve portion of the member 3|. The screw 62 is rigidly secured toan operating rod 64 which has sliding but non-rotatable telescoplcengagement with an operating rod (Fig. 2). The rod 65 extends rearwardlyfrom within the tubular feed screw and is secured at its rear end to acontrol handle 66. It will thus be seen that by rotating the handle 66,the control valve 6| may be moved longitudinally within the valvebushing bore through the rotatable screw 62 engaging the non-rotatablenut 63, and by the provision of the telescopically arranged .to bedescribed, into a bearing [23 in which the front end 29 interposedbetween the the feed piston 9 has reached its limit of forward feedingtravel relative to the-feed cylinder I, the manual control valve GI maybe positioned to supply liquid under pressure to the reverse feedpassages to efiect retraction of the feed piston 9 within the feedcylinder I, and the feed cylinder may then be fed forwardly in its guidebore on the trunnion support into a new feeding position, and thereafterforward feeding movement of the feed piston under the actuation ofliquidunder pressure may be resumed. Also, if desired, the bit rotating motormay be fed forwardly or rearwardly solely by the hand crank of the feedscrew entirely independently of the flow of liquid under pressure to thefeed cylinder. If, during forward feeding of the drill bit by liquidacting on the rear pressure area of the feed piston, it is desired tofeed the feed cylinder forwardly within its guide bore relative to thetrunnion support by means of the hand crankof the feed screw and so tomove the feed cylinder forwardly relative to the piston,

the hand crank of the feed the operator turns screw so as toadvance thefeed cylinder at arate greater than the rate of penetration of the drillbit, i. e. at a rate greater than the rate of the apparatus. This willobviously cause the normal feeding pressure on the drill bit to beincreased, and, as a result, the torque on the bit rotating means tobecome excessive so that the torque-controlled valve means would bemoved, by the improved torque reaction means shortly position to eflectventing of the liquid in the forward feed passages, in the same generalmanner as is described in the copending application mentioned above.Such venting of the liquid from the rear end of the feed cylindersenables manual feeding movement of the feed. cylinder relative piston,and the rate of manual cylinder advance is regulated by the capacity ofthe venting means.

The improved control means for the torquecontrolled valve meanscomprises a reciprocable member [20 splinai at IZI within a rearwardhollow portion I22 of the shaft 53. Supported with.- in the shaft 53 atthe rear of the member IN is. a of the motor armature shaft it:isiournaled,'and the motor shaft is: supported through this hearing bythe shaft 53 which is journaled in the bearings ll. The reciprocablemember 20 rotates; with the shaft 53 and has internal, spiral vanes orthreads [25- which are interengaged with similar spiral vanes or threads[*25 formed externally on the front end of the. armature shaft. It isaccording- Iy evident that the member 28, due to its: threaded engaement the motor shaft, moves axially relative to: the motor shaft uponrelative rotation between the member [221! and the motor shaft. Themotor shaft is centrally bored at $28;

and extending centrally through this bore a hollow operating rod 211.

flange [2t engageable with a. ball thrust bearing rod flange and aninternal flange 30 on the member E28- The rear end of the operating rodis annularly grooved. at 131,- and pins 32 on a shipper yoke R3 arereceived in. the: rod. groove so that when; the rod is movedtheshipper-yoke is swung about its to the feed This rod has: a front ITil the position shown in Fig.

pivotal mounting on a vertical pivot shaft I. The shipper yoke is'keyedto the shaft Ill and the latter is journaled in bearingssupported withinbearing brackein I35 integral with the rear-head element 43. Fixed by aset screw I 36 to the pivot shaft [3i is a lever l3! which projectswithin an annular groove I38 on the valve tappet 90 (Fig. 5). When theload on the bit rotating means is normal, the spring 2 holds the tappetto the right, as shown in Fig. 10, and, as a result, the member I20 isheld in its rearmost position on the motor shaft through the lever I31,shaft I34, shipper yoke I33, operating rod I21 and thrust hearing I29.

When the load on the bit rotating means exceeds a predetermined amount,i. e. if the resistance to drill bit rotation becomes excessive,relative rotation between the member I20 and the motor shaft occurs,thereby causing the member I 2!! to move axially in a forwarddirection'relative to the motor shaft, and, as a result, the valvetappet S0 is moved to the left in Fig. 10 through the operating rod,shipper yoke and lever against the tension of the spring 2. As the valvetappet ismoved to the left in Fig. 10, to the position shown in Fig. 11,the sleeve valve 88 is moved towards its seat or completely seated,thereby partially to close or completely to out 011. the flow of liquidunder pressure from the passage TI to the forward feed passage I9. Ifthe load on the bit rotating motor becomes even greater (which it mightdo despite the interruption of feeding liquid, were there application ofexcessive manual feeding pressure to the bit as above explained) i. e.if the resistance to bit rotation exceeds that which was previouslypredetermined as sumcient to warrant interruption of feeding, the member52E will move slightly further forwardly axially relative to the motorshaft, thereby moving the valve tappet 9|! further towards the left,moving the valve stem 9! relative to the then seated sleeve valve 88from the position shown in Fig. 11 to 12, and, as a result, the forwardfeed pasage I3 is vented through slot 99. ports I80, groove 88, ports95, groove 9, ports 98, longitudinal passage 91', chamber [05, groove"it, exhaust slot ME and exhaust passages fill and [88. It isaccordingly evident that variations in the load on the bit rotatingmeans, due ordinarily to variations in the pressure at which the bit isforced to the work, will automatically efiect control of the flow ofliquid to the forward feed passages'and interrupt the supply of liquidto the forward feed passages as overload of Simicient degree occurs, andon still greater overload vmt the forward passages. When thetorque-controlled valve means is in the position shown in Fig. 12', thetappet engages the shock der "4 on the bushing 89? to preclude furthermovement of the tappet toward the left. During; overloading of thebitrotating means by the man-'- ual feeding means, the overload of themotor causes the. pressure on the tappet produced by the increasedtorque to: exceed the combined pressures exerted by the Springs 93 and II2, thereby to cause the valve storm to move axially relative; to thethen seated sleeve valve which permits the liquid trapped in the feedcylinder at the rear side of the feed piston to discharge through. thefeed exhaust passages. This venting function is at all times undertorque control so that varied rates of venting. adapted todifierentrates of manna]; feedpare obtained, and if the feed exhaust passages areof sificient capacity the speed at which the operator manually feeds thefeed operating rods the valve may be operated irrespective of theposition of the control head relative to the trunnion support.Communicating with the rear end of the bore of the valve bushing is anexhaust chamber 61 connected to an exhaust passage 68. Surrounding thevalve bushing are grooves 69 and I connected by ports with the valvebushing bore. Groove 69 is the fluid supply groove and communicates withchamber 55 as shown in Fig. 1. Groove communicates with the forward endof the feed cylinder as later described. A chamber 1I also communicatesthrough ports with the valve bushing bore, while communicating with thefront end of the valve bushing bore is an exhaust chamber 12communicating with an exhaust passage I3. Chamber II is communicablewith the rear end of the feed cylinder, as later explained. The groove10 is connected by a passage 14 in the control head (Fig. 1) with apassage 15 in the head member I4, the latter passage communicating withthe interior of the feed piston rod I0. Ports 16 (Fig.

2 connect the interior of the feed piston rod with the feed cylinderbore at the front side of the feed piston 9. Liquid under pressure maybe supplied to the cylinder bore at the rear side of the feed pistonfrom the chamber II, when the latter is connected with the groove 69,through a passage 11, past a torque-controlled valve means, generallydesignated I8, to a forward feed passage 19 communicating with a passage80 in the head member Il. Thepassage 80 communicates with a recess 8|which is in turn connected, by a liquid conducting tube 82 extendingcentrally through the feed. piston rod with the cylinder bore at therear side of the feed piston (see Figs. 1, 2 and 6). The feed pistoncarries a packing 83 which sealingly engages the tube to preventleakage. When the control valve 6I is inone position the forward feedpassages communicating with the rear end of the feed cylinder bore atthe rear side of the feed piston are connected to the supply groove,while the reverse feed passages communicating with the feed cylinderbore at the forward side of the feed piston are connected to the exhaustchamber; and when the position of the valve is reversed the forward feedpassages are connected to exhaust while the reverse feed passages areconnected to the supplv. It will thus be seen that under the control ofthe manual control valve 6| liquid under pressure may be supplied to thefeed cylinder bore at either side of the feedpiston to effect forward orreverse feed as desired, and the manner in which theforward feed isinfluenced by the automatic torque-controlled valve means I8 will laterbe described.

The torque on the bit rotating means automatically regulates the flow ofliquid under pressure through the forward feed passages under thecontrol of the torque-controlled 'valve means above mentioned, therebyto control the feedin pressure on the drill bit. and when the torque onthe bit rotating means exceeds a predetermined amount the forwardfeeding pressure may be vented. As shown in Figs. 10 and 11. secured,within a transverse bore 85 in the control head 29 is a valve sleeve 86having a tapered annular valve seat 81 with whichthe tapered end of asleeve valve 88 is engageable. Reciprocably guided within the bore of abushing 89 is a valve tappet 90 having an integral valve stem 9|. Thevalve stem has a close sliding fit with the bore of the sleeve valve 88,and the sleeve valve is yieldingly held against a shoulder 92 on thevalve stem by a coil spring 93. The sleeve valve has an internal annulargroove 94 connectiblebyports 95' with a chamber 96 which surrounds thevalve. Formed in the valve stem 9 I is an axial passage 91 connectiblethrough ports 98 with the internal groove 94 in the sleeve valve in somepositions of the latter relative to the valve stem but normally sealedby the inner wall of the sleeve valve. When the sleeve valve 88 isagainst the shoulder 92, as shown in Figs. 10 and 11, and the sleevevalve is open a predetermined amount, communication of the ports 95 withthe chamber is cut off by the body of the sleeve valve, while when theparts are in the position shown in Fig. 12 with the sleeve valve seated,but not against the shoulder on the stem, the ports are in communicationwith the chamber 96 and with the ports 98. The valve sleeve 86 istransversely slotted at 99, and this slot is connected by a port I00with the chamber 96. The opposite side of the valve sleeve istransversely slotted at IN, and

this slot is connected by a port I02 with an enlarged bore I03, thelatter being communicable, under the sontrol of the sleeve valve, withthe chamber 96. The passage 11 communicates'with.

the slot IOI, and the slot 99 communicates with the forward feed passageI9. As shown in Fig. 12, a longitudinal groove I04 on the exterior ofthe valve sleeve connects a chamber I05 at the outer end of the valvesleeve bore with a transverse slot I06 which is connected'by passagesI01 and I08 with the exhaust. The valve stem 9| has a sliding fit withthe valve sleeve bore, and packings I09 sealingly engage the valve stemto reduce the possibility of leakage. Any leakage of liquid along thevalve stem may flow from the packing bore to the slot I06, as shown inFig. 12. Threaded within one end of the valve sleeve bore is a closureplug IIO, while threaded within the opposite end of the valve sleevebore is a plug I II with which the bushing 89 is integrally formed, andinterposed between the later plug and the valve tappet is a coil springII2 which constantly urges the tappet toward the right as viewed inFigs. '10 and 11. The coil spring is arranged within the bore of theplug III'. When the tappet is in the position shown in Fig. 10, it abutsthe inner end of the valve sleeve 86, and when the tappet is in itsextreme left hand position it may abut a shoulder II4 on the bushing 89.The pressure exerted by the spring II 2' is opposite to the direction inwhich the tappet is moved as a result of the torque reaction of the bitrotating means by the improved means shortly to be described, and thepressure exerted by the spring H2 is suflicient to hold the tappetagainst movement during normal full loaddrilling torque. The spring 93is made of such strength that it will not yield and permit movement ofthe valve stem 9I relative to the valve sleeve 88, with resultantcommunication of the passages 95 with the chamber 96, until a definiteoverloading of the bit rotating motor occurs. The spring 93 ispreferably made one quarter as strong as the spring H2 plus an amountsufficient to offset the changes due to the hydraulic pressure acting onthe difference between the areas of the sleeve valve'and valve stem.Noting that additional compression of the spring II2 will also have tobe efiected asoverload increases, it willbe apparent that a materialoverload, an excess desirably upwardsof twenty-five per cent ofnormal-full load,will'be necessary on the bit rotating tmotor before theslot 99 willbe connected to ven The bit rotating motor may be fedmanually by The fluid actuated feeding means is capable of imparting aforward feeding pressure to the drill bit sufficient to overload the bitrotating motor, and in the event of any change in drilling conditionsincreasing above normal the torque requirements, and in the event ofinitiation of overloading of. the bit rotating motor due to excessivetorque loads, the torque-controlled valve means is actuated in a mannerabove described, partially or completely to cut off flow of liquid tothe forward feed passages, thereby to slow down or stop forward feed andpreclude serious overloading of the bit rotating motor, and when themotor again operates at its normal load rating, forward feed isautomatically resumed or brought back to its desired rate as the casemay be. Thus the actual feeding pressure on the drill bit will always bekept at, or near, as an upperlimit, that required tokeep the bitrotating motor at its normal load rating, although the feeding pressuremay be greatly reduced or entirely removed if conditions of drillingbecome more severe. It will be apparent that large increases in torquerequirements will entirely interrupt-feeding liquid supply momentarilyand that slighter increases will serve to throttle the feeding liquidsupply,

and depending upon the pressure in the feed pressure supply line and thestrength of the spring H2, the normal full load position of the sleevevalve 88 may vary.

Cleansing liquid may be supplied through the drill rods to the drill bitfrom the liquid chamber 55 to a passage [40 in the control head 29, and

this passage is connected to a liquid conducting tube Ml secured at itsrear end to the control head and extending centrally through theoperating rod I21 and the motor armature shaft 46, as shown in Figs.land 3. The front end of the tube on may terminate within the hollowrear= ward portion of the shaft 53.

As a result of this invention it will be noted that an improved drillingapparatus of the high speed rotary type is provided whereb holes may bebored in relatively hard materials such as hard rock or the like. Alsoit is evident that an improved torque-controlled regulating means isprovided responsive to load changes on the bit rotating means wherebythe flow of feeding pressure to the feeding means may be automaticallyregulated in accordance with variations in the resistance to drill bitrotation, and the feeding.

means maybe automatically vented when the load on the bit rotating meansis caused to exceed av predetermined amount. It will further be evidentthat by the provision of the improved operating means for thetorque-controlled valve means, the mounting structure for the bitrotating motor is not only simplified over previous known devices butalso the controlling action is rendered more positive and direct. Otheruses and advantages of the improved drilling apparatus will beclearlyapparent to those skilled in the art.

While there is in this application specifically described one form whichthe invention may assume in practice, it will be understood that thisform of the same is shown for purposes of illustration and that theinvention may be modified and embodied in various other forms withoutdeparting from its spirit or the scope of the appended claims.

What I claim as new and desire to secure by Letters Patent is:

1. In a drilling apparatus, the combination comprising a motor forrotating a drill bit, said "latter, operating medium actuated means forfeeding the drill bit including a power operated feeding elementsubjectable to the action of .power medium to effect positively feed ofthe drill bit toward the'work during drilling, and means for regulatingthe supply of operating medium to said feeding means automatically inaccordance with variations in resistance to drill bit rotation, saidautomatic regulating means having operating means operatively connectedin the drive between said motor power shaft and said driven shaft andactuated on relative rotation between said shafts.

2. In a drilling, apparatus, the combination comprising a motor forrotating a drill bit, said .motor having a power shaft, feeding meansfor said drill bit and having limited rotary movement with respect tothe motor power shaft and operative on such movement to effect a changein the supply of motive power to said feeding means.

3. In a drilling apparatus, the combination comprising a motor forrotatin a drill bit, said motor having a power shaft, feeding means forfeeding the drill bit including a power operated feeding elementsubjectable to the action of power medium to effect positively feed ofthe drill bit toward the work during drilling, and means for regulatingthe supply of motive power to said feeding means automatically inaccordance with variations in resistance to drill bit rotation, saidautomatic regulating means including operating means having acontrolmember connected in driving relation between the motor power shaft andthe drill bit, said control member having limited axial movement withrespect to the motor power shaft produced by load changes on the drillbitand operative on such movement to effect a change in the supply ofmotive power to said feeding means.

4. In a :drilling apparatus, the combination comprising a motor forrotating a'drill'bit, said motor having a power shaft, feeding means foring a control member connected in driving relation between the motorpower shaft and the drill bit, said control member having limited rotaryand axial movements with respect to the motor power shaft produced byload changes on the drill bit and operative on such movements to effecta change in the supply of motive power to said feeding means.

5. A drilling-apparatus comprising, in combidrill bit for rotating thedrill bit in the same direction as said shaft, said operativeconnections yieldable upon predetermined increase in resistance to drillbit rotation, operating medium actuated feeding means for said drillbit, and means for controlling the supply of operating medium to saidfeeding means automatically in accordance with variations in theresistance to rotation of said drill bit, said controlling meansoperatively connected to an element of said operative connectionsbetween said drill bit and shaft and governed by relative movementbetween said shaft and drill bit on variation in resistance to drill bitrotation to preclude application of feeding pressures in excess ofdesired values to the drill bit.

6. A drilling apparatus comprising, in combination, a rotary drill bit,a motor having a power shaft for rotating said drill bit to cause thesame to effect a drilling operation by a boring action, fluid actuatedfeeding means for said drill bit including amovable feeding elementsubiectable to the action of pressure fluid for positively feeding thedrill bit toward the work during drilling, and means for controlling thesupply of fluid to said feeding means, said controlling means includingtorque-controlled valve means, and operating means for said valve meansoperatively connected between said motor power shaft and thebit andoperating automatically in accordance with variations in the resistanceto rotation of said drill bit, to precludeapplication of feedingpressures in excess of desired values to the drill bit.

'1. Drilling apparatus as claimed in claim 5, characterized in that saidmeans for controlling the supply of operating, medium to said feedingmeans includes an operating element having movement with respect to themotor power shaft as the resistance. to rotation of said drill bitvaries. a

8. Drilling apparatus as claimed in claim 5, characterized in that saidmeans for controlling the supply of operating medium to said feedingmeans includes an operating element having rotary movement with respectto the motor power shaft as the resistance to rotation of said drill bitvaries. V

9. Drilling apparatus as claimed in claim 5, characterized in that saidmeans for controlling the supply of operating medium to said feedingmeans includes an operating element having axial movement with respectto the motor power shaft as the resistance to rotation of said drill bitvaries.

10. Drilling apparatus as claimed in claim 5, characterized in thatsaidmeans for controlling the supply of operating medium to said feedingmeans includes an operating element having axial and rotary movementswith respect to the motor power shaft as the resistance to rotation ofsaid drill bit varies.

11. Drilling apparatus comprising, in combination, a rotary drill bit, amotor having a power shaft for rotating said drill bit to cause the sameto effect a drilling operation by a boring action, feeding means forsaid drill bit, and means for controlling the operation of said feeding'means automatically in accordance with variations in the resistance torotation of said drill bit to preclude application of feeding pressuresin excess of desired values to the drill bit. said I 2,839,801 nation, arotary drill bit, a motor having a power feed controlling meansoperatively connected to said motor power shaft and including anoperating element connected for rotation with the drill bit and havingconnection with said motor power shaft permitting relative rotationbetween said operating element and said power shaft, said connectionbetween said operating element and said power shaft compelling relativeaxial movement between saidoperating element and said power shaft uponrelative rotation therebetween.

12. A drilling apparatus comprising, in combination, a rotary drill bit,a motor having a power shaft for rotating said drill bit, operativeconnections between said drill bit and said power shaft including'adriven element alined with said power shaft and rotatable thereby in thesame direction therewith, feeding means for said drill bit, and meansfor controlling the operation of said feeding means, said feedcontrolling means operatively connected in the drive between said motorpower shaft and said driven element and being adapted to operateautomatically in accordance with the variations in resistance todrilling to preclude application of feeding pressures in excess of'desired values to the drill bit.

13. A drilling apparatus comprisin in combination, a rotary drill bit, amotor having a power shaft for rotating said drill bit, operativeconnections between said drill bit and said power shaft including a.driven element alined with said power shaft, feeding means for-saiddrill bit, and means for controlling the operation of said feedingmeans, said feed controlling means operatively connected in the drivebetween said motor power shaft and said driven element and being adaptedto operate automatically in accordance with the variations in resistancetodrilling to preclude application of feeding pressures in excess ofdesired values to the drill bit, said feed controlling means includingan operating element having an axial splined connection with said drivenelement.

14. A drilling apparatus comprising, in combination, a rotary drill bit,a motor having a power shaft for rotating said drill bit, operativeconnections between said drill bit and said power shaft includingadriven element alined with bit and means for controlling the operationof said feeding means, said feed controlling means operatively connectedin the drive between said motor'power shaft and said driven element andbeing adapted to operate automatically in accordance with the variationsin resistance to drilling to preclude application of feeding pressuresin excess of desired values' to the drill bit, said feed controllingmeans including an operating element which constitutes a connectionbetween said motor power shaft and said driven element by which thelatter is driven in the same direction as the former and which elementis movable relative to said power shaft and said driven element.

l5. A'drilling apparatus comprising, in combination, a rotary drill bit,a motor havinga power shaft for rotating said drill bit, operativeconnections between said drill bit and said power shaft-including adriven element alined with said power shaft, feeding means for saiddrill bit, and means for controlling the operation of said feedingmeans, said feed controlling means operatively connected in the drivebetween said motor power shaft and said driven element and being adaptedto operate'automatically in accordance with the variations in resistanceto drilling to preclude application of feeding pressures in excess' ofdesired values to the drill bit, said feed bination, a rotary drill bit,a motor for rotating said drill bit, said motor having a casingcontaining a rotor having a power shaft, feeding means for said drillbit for exerting a feeding pressure thereon irrespective of whether thedrill,- ing apparatus is supported to drill holes above or below thehorizontal, and means operatively connected in the drive between themotor power.

shaft and the drill bit for controlling the operation of said feedingmeans, said feed controllng means being adapted to operate automaticallyin accordance with variations in the resistance to drilling to precludeapplication of feeding pressures in excess of desired valuesto the drillbit.

17. A drilling apparatus comprisingrin combination, a rotary drill bit,a motor for rotating said drill bit to cause the same to effect adrilling operation by a boring action, said motor having a non-rotatableeasing containing a rotor having a power shaft, feeding means for saiddrill bit, and means for controlling the operation of said feeding meansautomatically in ac-' cordance with variations in the resistance todrilling to preclude application of feeding pressures in excess ofdesired values to the drill bit,

said controlling means including torque-controlled regulating means andoperating means therefor connected in driving relation between the motorpower shaft and the drill bit and effecting rotation of the-latter inthe same direction as the former.

18. A drilling apparatus comprising, in combination, a rotary drill bit,a motor for rotating said drill bit to cause the same to effect a drilling operation by a boring action, said motor having a non-rotatablecasing containing a' rotor having a power shaft, feeding means for thedrill bit including a power operated feeding element subiectable to afeeding pressure for posisaid drill bit to cause the same to effect adrilling operation by a boring action, said motor having a non-rotatablecasing containing a rotor having a power shaft, feeding means for thedrill bit, and means for controlling the operation of said feedingmeans, said feed controlling means including means governed byvariations in the resistance to drilling for precluding the applicationof feeding pressures in excess'of the desired values to the drill bit,and said last mentioned means including an element'movable to controlthe feeding pressure and means for moving said element operativelyconnected with said power shaft and turning as the latter turns but soconstructed and arranged that relative motion proportional to the torqueexerted by said power shaft in effecting drilling occurs between thesame and said shaft, said element moving means having axial motion withrespect to said power shaft.

has bothrotary and axial motions with respect to said power shaft. I

22. In a drilling apparatus, in combination, a motor for rotating adrill bit, said motor having a power shaft,driving connections betweensaid motor power shaft and the drill bit including a driven shaftoperatively connected to said power shaft for rotation in the samedirection with relative rotation in opposite directions between saidpower shaft and said driven shaft to effect opposite changes in feedingpressure.

23. In a drilling apparatus, in combination, a motor for rotating adrill bit, said motor having a power shaft, driving connections betweensaid motor power shaft and'the drill bit including a driven shaftoperatively connected to said power shaft for rotation in the samedirection with but also for rotation relative to the latter, fluidactuated, feeding means for the drill bit, and means for controlling thesupply of operating fluid to said feeding means automatically in tivelyfeeding the drill bit toward the workduring drilling, and means forcontrolling the operation of said feeding means, said feed controllingmeans including means governed by variations in the resistance todrilling for precluding application of feeding pressures in excess ofthe desired values to the drill bit, said last mentioned means includingan element movable tocontrol the feeding pressure and means for movingsaid element operatively connected with saidpower shaft and turningasthe latter turns but so constructed and arrangedthat relative motionproportional to the torque'exerted by said power shaft in effectingdrilling occurs between the same and said shaft.

19. Drilling appaartus as claimedin claim 18,

characterized in that said means between which and said power shaftthere occurs relative motion proportional to the torque exerted by thepower shaft for effecting drilling has rotary motion with respect tosaid power shaft.

20. Drilling apparatuscomprlsing, in combination, a rotary drill bit, amotor for rotating accordance with the resistance to drill bit rotation,said feed controlling means including means operatively connected tosaid driving connections 5 and actuated on relative rotation betweensaid to cause said coaxial member to rotate in the same direction assaid power driven member but yieldable to permit limited relativerotation between them as the resistance to rotation of said secondmember increases under increased resistance to drilling, means forfeeding the bit as the same is rotated by the second member, and meansgoverned by the relative rotation between said members forpredeterminedly varying the feeding force exerted by said feeding means.

wm w. mom.

21. Drilling apparatus asclaimed in claim 20, characterized in that saidelement moving means

